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Laboratory studies are carried out on the effect of Accrus calamus L. oil vapours an egg development; fecundity and; fertility of 'Oysderus. cinguiofus Fabr. The results indicated that no significant effect of treatments i. e. different dos^s on the percent of hatching was observed, but a significant difference of adult emergences based on eggs couid be observed at different exposure periods i. e. as the exposure period increases the percent of aduits emergence decreased and vice versa. The vapours affected the hatching of eggs of all age groups. The nymphs that hatches: out from some of these eygs did not moult but died particularly at high dose. A slight carry over effect of the A. calamus oil vapours were '«alsonoted.